The ALDH1B1 Knockout HCT 116 Polyclonal Cells represent a mixed population of CRISPR/Cas9-edited HCT 116 human colorectal carcinoma cells harboring a spectrum of loss-of-function indels at the ALDH1B1 locus. This polyclonal configuration avoids the genetic bottlenecks of clonal selection, thereby preserving cellular heterogeneity found in tumor tissues and enabling robust evaluation of gene function in a context that better mimics the natural variability of gene inactivation. It is particularly advantageous for pooled functional genomics screens, drug sensitivity profiling, and studies requiring population-level phenotypic responses.
HCT 116 is a widely utilized human colorectal carcinoma cell line of epithelial origin, characterized by high-frequency microsatellite instability (MSI-H) stemming from a biallelic MLH1 mutation and a heterozygous KRAS G13D activating mutation. The MSI-H phenotype confers defects in DNA mismatch repair, leading to a hypermutable genotype, while oncogenic KRAS promotes constitutive MAPK and PI3K pathway signaling. These genetic features make HCT 116 cells a valuable model for investigating mechanisms of apoptosis evasion, chemotherapeutic drug resistance, and the biology of cancer stem cells. The combination of ALDH1B1 knockout with this genetic background provides a unique opportunity to study interactions between aldehyde metabolism and key oncogenic pathways.
ALDH1B1 encodes a mitochondrial aldehyde dehydrogenase that catalyzes the NAD+-dependent oxidation of retinaldehyde to retinoic acid, as well as the detoxification of acetaldehyde and 4-hydroxynonenal. The enzyme is regulated by Wnt/??-catenin signaling (via Wnt3a, Frizzled, ??-catenin, TCF/LEF), HNF4??, and the Nrf2-KEAP1 oxidative stress pathway. Its retinoic acid product activates nuclear receptors RAR and RXR, which transcriptionally upregulate stemness genes such as LGR5 and CD44. By metabolizing 4-hydroxynonenal, ALDH1B1 also mitigates oxidative stress. Knockout abolishes retinoic acid signaling, reduces stemness factor expression, impairs reactive aldehyde clearance, and may alter Wnt/??-catenin pathway activity.
In the HCT 116 background, ALDH1B1 knockout eliminates the conversion of retinaldehyde to retinoic acid and the detoxification of 4-hydroxynonenal, consequently attenuating retinoic acid-dependent stemness and heightening sensitivity to oxidative stress-induced apoptosis. Given the highly proliferative and apoptosis-resistant nature of HCT 116 cells driven by mutant KRAS, this model allows for detailed dissection of how aldehyde metabolism interfaces with DNA damage responses, mitochondrial integrity, and cancer stem cell self-renewal. It serves as a relevant platform for exploring the role of ALDH1B1 in colorectal tumor progression and for evaluating compounds that modulate aldehyde dehydrogenase activity.
This polyclonal knockout population is suited for a broad spectrum of research applications, including colorectal cancer stem cell biology, aldehyde toxicity and metabolism, retinoic acid signaling pathway analysis, and high-throughput screening of ALDH-targeted therapies. Key validation and functional assays include the Aldefluor ALDH activity assay to confirm loss of enzymatic function, Western blotting for ALDH1B1 protein expression, RT-qPCR and flow cytometric quantification of LGR5 and CD44, retinoic acid ELISA, MTT cell viability tests under 4-hydroxynonenal challenge, and spheroid formation assays to assess stemness capacity. Comprehensive transcriptomic changes can be profiled by RNA-seq. For further technical details, please contact Ascent Research.
